Mark 6:18
For John had said unto Herod, It is not lawful for thee to have thy brother’s wife.
Mark 6:18 (KJV)
Context
John the Baptist speaks here to Herod Antipas, the ruler of Galilee, about the ruler’s marriage to Herodias. Herodias had been the wife of Herod’s brother Philip, and she was still living when Herod took her as his own. John’s words are a direct moral indictment, not a matter of personal opinion. His confrontation of a powerful ruler fits his prophetic calling to prepare the way for Jesus Christ by calling people to repentance, regardless of their rank.
Meaning
John’s declaration rests on the Mosaic Law. Leviticus 18:16 explicitly prohibits sexual relations with a brother’s wife, describing such an act as unclean and dishonoring to the brother. Because Philip was still alive, Herod’s union with Herodias was adulterous and unlawful. John’s statement is therefore not a new or private standard but an appeal to God’s revealed moral law, which binds rulers and subjects alike. The law was given to set Israel apart as holy, and John applies it directly to a public scandal in the royal household.
Biblical connections
The command John cites is rooted in the holiness code of Leviticus, where God set clear boundaries for marriage and sexual purity. The same moral standard is reinforced in the New Testament, where marriage is upheld as a faithful covenant. John’s boldness also foreshadows the rejection Jesus Himself would face: the prophet who speaks God’s truth is silenced, but the truth he proclaims is not diminished. The continuity between the Old Testament law and John’s prophetic message shows that God’s moral character does not change with human authority or convenience.
Application
Mark 6:18 calls believers to examine their own lives for areas where God’s commands have been set aside for comfort or advantage. It also teaches that speaking truth to power is a responsibility, not an option. John was not intimidated by Herod’s position, and his example encourages Christians to stand for righteousness even when it is unpopular or costly. The verse warns that sin in high places is not hidden from God, and it reminds us that obedience to Him often carries a price. Faithfulness, not approval, is the standard by which our words and actions are measured.
Reflection
John’s confrontation led to imprisonment and eventually execution, yet his words remain a lasting testimony to the cost of faithfulness. Herodias resented the rebuke and seized the opportunity to silence him, but the truth he spoke could not be silenced. This verse challenges us to consider whether we are willing to uphold God’s standards when doing so brings opposition. It also comforts us with the assurance that our faithfulness to God is never wasted, even when its reward is delayed or hidden.
